题目描述
In this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.
输入
The input will consist of a series of integers n, one integer per line.
输出
For each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit signed integer.
样例输入
1
100
样例输出
1
5050
时间限制: 1 Sec 内存限制: 128 MB
代码实现:
#include<stdio.h>
int main()
{
int n;
while(~scanf("%d", &n))
{
int sum = 0;
while(n)
{
sum += n;
n--;
}
printf("%d\n\n", sum);
}
return 0;
}